1. Technical Field
The present invention relates to image rendering, and more particularly to a system and method for generating a 3D volumetric mask.
2. Discussion of Related Art
Methods for generating a 2D image from volumetric data can be classified as indirect and direct volume rendering techniques. Indirect methods generate and render an intermediate representation of the volume data, while direct methods display voxel data by evaluating an optical model, which describes how the volume emits, reflects, scatters, absorbs, and occludes light. Voxel densities are mapped to physical quantities describing light interaction at respective points in a 3D-space. During image synthesis, light propagation is computed by integrating light interaction effects along viewing rays based on an optical model. The corresponding integral is known as the volume rendering integral.
Digital surfaces are represented by sets of polygons (e.g., triangles or quadrilaterals). These surfaces may be arbitrarily generated, obtained from the segmentation of a three-dimensional (3D) image (medical or non-medical), or obtained from a 3D point cloud. These points may be acquired from real-life objects, using point trackers, such as optical or magnetic based trackers.
The 3D volume array of data, typically used in volume rendering, is assembled using a series of consecutive slices through a solid body being scanned, where each slice is a two-dimensional (2D) image array of data points. Each grid value of a 2D image array is called a picture element, or pixel, while each grid value of a 3D volume array is called a volume element, or voxel. The 3D volumetric information can also be obtained by other means such as Computed Tomography (CT), Diffuse Optical Spectroscopy (DOS), positron emission tomography (PET), ultrasound scanning, etc.
A surface of the 3D volumetric array may need to be filled in with information, and therefore a volume needs to be generated from the surface. Each voxel inside the volume may be given a specific quantitative value.
To be able to fill the surface of the 3D volumetric array it is important to be able to combine and merge multimodal information such as geometric information from surfaces and other types of volumetric data.
The amount of data involved in the DVR increases with the volume dimensionality.
Therefore, a need exists for an efficient algorithm for volumetric rendering, which can be used in a variety of cases.